This invention relates to new .beta.-carbolin-3-carboxylic acid derivatives, and to methods of preparing them.
The specification of Canadian Pat. No. 786,351 discloses .beta.-carbolin-3-carboxylic acid amides and derivatives substituted in the 1-position by alkyl containing no more than 5 carbon atoms, trifluoromethyl, phenyl or benzyl, as well as two specific compounds having no substituent at the 1-position, viz. .beta.-carbolin-3-carbohydrazide and .beta.-carbolin-3-carboxylic acid amide.
Danish Patent Specification Number 98,436 discloses a method of preparing methyl .beta.-carbolin-3-carboxylate.